Hsu Ming-Lun, Chen Fang-Ching, Kao Hung-Chan, Cheng Cheng-Kung
Dental School, National Yang-Ming University, Taipei, Taiwan.
Int J Oral Maxillofac Implants. 2007 Mar-Apr;22(2):301-9.
To evaluate the influence of the stress/strain distribution in bone around an anterior maxillary implant using 2 types of bone and under 3 different loads.
A premaxillary finite element model featuring an implant and its superstructure was created. Six different testing conditions incorporating 2 types of cancellous bone (high density and low density) under 3 different loading angles (0, 30, and 60 degrees) relative to the long axis of the implant were applied in order to investigate resultant stress/strain distribution.
The maximum equivalent stress/strain increased linearly with the increase of loading angle. For each 30-degree increase in loading angle, the maximum equivalent stress in cortical bone increased, on average, 3 to 4 times compared with that of the applied axial load. In addition to loading angle, bone quality also influenced resultant stress distribution. For the low-density bone model, a substantial strain in the cancellous bone was found not only near the implant neck but also at the implant apex.
To achieve a favorable prognosis under off-axis loading of an anterior maxillary implant, careful case selection for appropriate bone quality and precise occlusal adjustment should be attempted to optimally direct occlusal force toward the long axis of the implant.
使用两种类型的骨并在三种不同载荷下，评估上颌前部种植体周围骨内应力/应变分布的影响。
创建一个包含种植体及其上部结构的前上颌骨有限元模型。应用六种不同的测试条件，包括相对于种植体长轴的三种不同加载角度（0、30和60度）下的两种类型的松质骨（高密度和低密度），以研究所得的应力/应变分布。
最大等效应力/应变随加载角度的增加呈线性增加。加载角度每增加30度，皮质骨中的最大等效应力平均比施加的轴向载荷增加3至4倍。除加载角度外，骨质量也影响所得的应力分布。对于低密度骨模型，不仅在种植体颈部附近而且在种植体顶端的松质骨中都发现了大量应变。
为了在上颌前部种植体的非轴向加载下获得良好的预后，应尝试仔细选择合适骨质量的病例并进行精确的咬合调整，以将咬合力最佳地引导至种植体长轴方向。
